我试图在android中编写音乐播放器代码。我想显示歌曲，艺术家和专辑图像的当前标题。 活动是： 包com.example.getmusic;
import java.io.IOException;
import java.util.ArrayList;
import com.example.getmusic.PlayMusicService.LocalBinder;
import android.media.AudioManager;
import android.media.MediaMetadataRetriever;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.provider.MediaStore;
import android.provider.MediaStore.Audio;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.res.Configuration;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.telephony.TelephonyManager;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.SeekBar.OnSeekBarChangeListener;
public class GetMusic extends Activity implements OnGestureListener {
static Handler seekhandler=new Handler();
boolean isServiceConnected=false;
PlayMusicService playServ;
static TextView tv1,tv2,tv3;
Button previous,next;static ImageView img;static GestureDetector gDetector;
int pausePressed=1;static SeekBar sb;
int currentIndex=0;Cursor cursor;GenericSongClass GSC;
static MediaPlayer mediaPlayer;static int posofaudiotrack;
private ServiceConnection conn=new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) {
// TODO Auto-generated method stub
isServiceConnected=false;
}
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
// TODO Auto-generated method stub
LocalBinder binder=(LocalBinder)service;
playServ=binder.getService();
isServiceConnected=true;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_get_music);
gDetector= new GestureDetector(this);
tv1=(TextView)findViewById(R.id.textView1);
tv2=(TextView)findViewById(R.id.textView2);
tv3=(TextView)findViewById(R.id.textView3);
getSongs();
img=(ImageView)findViewById(R.id.imageView1);
sb=(SeekBar)findViewById(R.id.seekBar1);
try{
Intent serv = new Intent(this,PlayMusicService.class);
bindService(serv, conn, Context.BIND_AUTO_CREATE);
System.out.println("in try calling service");
startService(serv);
}
catch(Exception e){
System.out.println("Exception is"+e);
}
System.out.println("after binding");
/*
try {
playSong(0);
}
catch(Exception e){
System.out.println("Exception is"+e);
}*/
//PlayMusic p=new PlayMusic();
// p.execute();
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
if (isServiceConnected) {
unbindService(conn);
isServiceConnected = false;
}
}
public static void mediaPlayerPause()
{
if(mediaPlayer!=null)
{
mediaPlayer.pause();
posofaudiotrack=mediaPlayer.getCurrentPosition();
}
}
public void mediaPlayerResume()
{
if(mediaPlayer!=null&&!mediaPlayer.isPlaying())
{
mediaPlayer.seekTo(mediaPlayer.getCurrentPosition());
mediaPlayer.start();
}
}
public class PlayMusic extends AsyncTask<Void, Void, Void>
{
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
getSongs();
return null;
}
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
// TODO Auto-generated method stub
super.onConfigurationChanged(newConfig);
}
public static ArrayList<GenericSongClass> songs = null;
public void getSongs() {
Toast.makeText(getApplicationContext(), "in BindAllSongs()", Toast.LENGTH_SHORT).show();
String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";
final String[] projection = new String[] {
MediaStore.Audio.Media.DISPLAY_NAME,
MediaStore.Audio.Media.ARTIST,
MediaStore.Audio.Media.DATA,MediaStore.Audio.Media.COMPOSER,MediaStore.Audio.Media.TITLE,MediaStore.Audio.Media.ALBUM
};
final String sortOrder = MediaStore.Audio.AudioColumns.TITLE
+ " COLLATE LOCALIZED ASC";
try {
Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
cursor = getBaseContext().getContentResolver().query(uri,
projection, selection, null, sortOrder);
/* int column_index = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
String s=cursor.getString(column_index);*/
// Toast.makeText(getApplicationContext(), "path is"+s, Toast.LENGTH_SHORT).show();
// System.out.println("path is"+s);
if (null == cursor) {
Log.e("error","cursor is null");
// If the Cursor is empty, the provider found no matches
} else if (cursor.getCount() < 1) {
Log.i("info","cursor count<1");
} else {
songs = new ArrayList<GenericSongClass>(cursor.getCount());
cursor.moveToFirst();
int colIndex=cursor.getColumnIndex(MediaStore.Audio.Media.DATA);
String path = cursor.getString(colIndex);
// Toast.makeText(getApplicationContext(), "PATH IS"+path, Toast.LENGTH_SHORT).show();
System.out.println("PATH IS"+path);
while (!cursor.isAfterLast()) {
GSC = new GenericSongClass();
GSC.songTitle = cursor.getString(0);
GSC.songArtist = cursor.getString(1);
GSC.songData = cursor.getString(2);
GSC.songComposer=cursor.getString(3);
GSC.title=cursor.getString(4);
GSC.album=cursor.getString(5);
songs.add(GSC);
cursor.moveToNext();
}
// Toast.makeText(getApplicationContext(), "songs first is"+songs.get(0).songTitle, Toast.LENGTH_SHORT).show();
// Toast.makeText(getApplicationContext(), "songs length is"+songs.size(), Toast.LENGTH_SHORT).show();
mediaPlayer=new MediaPlayer();
mediaPlayer.setOnPreparedListener(new OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
// TODO Auto-generated method stub
Log.e("I", "Media player has been loaded to memory !");
}
});
/*for(int i=0;i<songs.size();i++){
if(mediaPlayer.isPlaying())
mediaPlayer.reset();
String p=songs.get(i).songData;
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);*/
}
}
catch (Exception ex) {
Toast.makeText(getApplicationContext(), "exception is"+ex, Toast.LENGTH_SHORT).show();
Log.i("ex is",ex.toString());
} finally {
if (cursor != null) {
cursor.close();
}}
}
protected void getPreviousSong()
{
if(currentIndex==0)
currentIndex=songs.size()-1;
else{
currentIndex=currentIndex-1;
}
playSong(currentIndex);
}
protected void getNextSong() {
// TODO Auto-generated method stub
if(currentIndex == songs.size()-1){
currentIndex=0;
}
else
{
currentIndex=currentIndex+1;
}
playSong(currentIndex);
}
private void playSong(int index) {
// TODO Auto-generated method stub
try{
mediaPlayer.reset();
String p=songs.get(index).songData;
System.out.println("Song title is"+songs.get(1).songTitle+"artist"+songs.get(1).songArtist+"composer is"+songs.get(1).songComposer.valueOf(0)+"title is"+songs.get(1).title);
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
tv1.setText(songs.get(index).title);
tv2.setText(songs.get(index).album);
tv3.setText(songs.get(index).songArtist);
// tv3.append(songs.get(index).album);
mediaPlayer.setDataSource(p);
MediaMetadataRetriever mmr = new MediaMetadataRetriever();
byte[] rawArt;
Bitmap art = null;
BitmapFactory.Options bfo=new BitmapFactory.Options();
mmr.setDataSource(p);
rawArt = mmr.getEmbeddedPicture();
if (null != rawArt)
art = BitmapFactory.decodeByteArray(rawArt, 0, rawArt.length, bfo);
img.setImageBitmap(art);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();;
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
Log.d("exc","exception is"+e.toString());
System.out.println("exception is"+e.toString());
}
try {
mediaPlayer.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "prepate exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "prepate exception is"+e.toString(), Toast.LENGTH_SHORT).show();
System.out.println("exception is"+e.toString());
}
mediaPlayer.start();
sb.setMax(mediaPlayer.getDuration());
seekUpdation();
sb.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
seekhandler.removeCallbacks(run);
mediaPlayer.seekTo(seekBar.getProgress());
seekhandler.postDelayed(run, 1000);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
seekhandler.removeCallbacks(run);
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
}
});
mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mediaPlayer) {
// TODO Auto-generated method stub
pausePressed=1;
playServ.getNextSong();
}
});
}
Runnable run = new Runnable() {
@Override
public void run() {
seekUpdation();
}
};
public void seekUpdation() {
sb.setProgress(mediaPlayer.getCurrentPosition());
seekhandler.postDelayed(run, 1000);
}
public class GenericSongClass {
String songTitle = "";
String songArtist = "";
String songData = "";
String songComposer="";
String title="";
String album="";
String isChecked = "false";
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.get_music, menu);
return true;
}
@Override
public boolean onDown(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onTouchEvent(MotionEvent me) {
return gDetector.onTouchEvent(me);
}
@Override
public boolean onFling(MotionEvent start, MotionEvent finish, float velocityX,
float velocityY) {
pausePressed=1;//int x=playServ.getCurrentIndex();
// TODO Auto-generated method stub
if(start.getRawX() < finish.getRawX())
{
//Toast.makeText(getApplicationContext(), "chanegd", Toast.LENGTH_SHORT).show();
if(playServ!=null){
/* if(x==0)
x=songs.size()-1;
else{
x=currentIndex-1;
}
tv1.setText(songs.get(x).title);
tv2.setText(songs.get(x).album);
tv3.setText(songs.get(x).songArtist);
tv3.append(songs.get(x).album);*/
playServ.getPreviousSong();}
else
System.out.println("ms null");
}
else if(start.getRawX()>finish.getRawX())
{
//Toast.makeText(getApplicationContext(), "changed on other", Toast.LENGTH_SHORT).show();
Log.d("onFLing","in onFling");
if(playServ!=null){
/*
if(x == songs.size()-1){
x=0;
}
else
{
x=x+1;
}
tv1.setText(songs.get(x).title);
tv2.setText(songs.get(x).album);
tv3.setText(songs.get(x).songArtist);
tv3.append(songs.get(x).album);*/
playServ.getNextSong();
}
else
System.out.println("ms null");
}
return true;
}
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
System.out.println("PAUSEPRESSED"+pausePressed);
if(pausePressed==1){
pausePressed=0;
playServ.mediaPlayerPause();
}else if(pausePressed==0){
pausePressed=1;
//mediaPlayer.seekTo(posofaudiotrack);
playServ.mediaPlayerResume();
}
return true;
}
}
and the Service is:
package com.example.getmusic;
import java.io.IOException;
import java.util.ArrayList;
import com.example.getmusic.GetMusic.GenericSongClass;
import android.app.Service;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.AudioManager;
import android.media.MediaMetadataRetriever;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import android.widget.SeekBar;
import android.widget.Toast;
import android.widget.SeekBar.OnSeekBarChangeListener;
public class PlayMusicService extends Service{
MediaPlayer mp;int currentIndex=0;
ArrayList<GenericSongClass> songs=GetMusic.songs;int pausePressed=1;
IBinder servbind=new LocalBinder();
public class LocalBinder extends Binder{
PlayMusicService getService()
{
return PlayMusicService.this;
}
}
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return servbind;
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
mp=new MediaPlayer();
mp.setOnPreparedListener(new OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer arg0) {
// TODO Auto-generated method stub
System.out.println("in onPrepared");
}
});
mp.setOnCompletionListener(new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mediaPlayer) {
// TODO Auto-generated method stub
pausePressed=1;
getNextSong();
}
});
mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
try{
System.out.println("in try");
playSong(0);
}
catch(Exception e){
System.out.println("in catch and exception is "+e.getMessage());
}
}
public void playSong(int index){
// TODO Auto-generated method stub
try{
System.out.println("in playsong");
mp.reset();
String p=songs.get(index).songData;
System.out.println("Song title is"+songs.get(1).songTitle+"artist"+songs.get(1).songArtist+"composer is"+songs.get(1).songComposer.valueOf(0)+"title is"+songs.get(1).title);
mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
GetMusic.tv1.setText(songs.get(index).title);
GetMusic.tv2.setText(songs.get(index).album);
GetMusic.tv3.setText(songs.get(index).songArtist);
GetMusic.tv3.append(songs.get(index).album);
mp.setDataSource(p);
MediaMetadataRetriever mmr = new MediaMetadataRetriever();
byte[] rawArt;
Bitmap art = null;
BitmapFactory.Options bfo=new BitmapFactory.Options();
mmr.setDataSource(p);
rawArt = mmr.getEmbeddedPicture();
if (null != rawArt)
art = BitmapFactory.decodeByteArray(rawArt, 0, rawArt.length, bfo);
GetMusic.img.setImageBitmap(art);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();;
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "exception is"+e.toString(), Toast.LENGTH_SHORT).show();
Log.d("exc","exception is"+e.toString());
System.out.println("exception is"+e.toString());
}
try {
mp.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "prepate exception is"+e.toString(), Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Toast.makeText(getApplicationContext(), "prepate exception is"+e.toString(), Toast.LENGTH_SHORT).show();
System.out.println("exception is"+e.toString());
}
mp.start();
GetMusic.sb.setMax(mp.getDuration());
seekUpdation();
GetMusic.sb.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
GetMusic.seekhandler.removeCallbacks(run);
mp.seekTo(seekBar.getProgress());
GetMusic.seekhandler.postDelayed(run, 1000);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
GetMusic.seekhandler.removeCallbacks(run);
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
}
});
}
Runnable run = new Runnable() {
@Override
public void run() {
seekUpdation();
}
};
public void seekUpdation() {
GetMusic.sb.setProgress(mp.getCurrentPosition());
GetMusic.seekhandler.postDelayed(run, 1000);
}
public int getCurrentIndex(){
return currentIndex;
}
public void mediaPlayerPause()
{
if(mp!=null)
{
mp.pause();
//pos=mediaPlayer.getCurrentPosition();
}
}
public void mediaPlayerResume()
{
if(mp!=null&&!mp.isPlaying())
{
mp.seekTo(mp.getCurrentPosition());
mp.start();
}
}
public void getPreviousSong()
{
if(currentIndex==0)
currentIndex=songs.size()-1;
else{
currentIndex=currentIndex-1;
}
playSong(currentIndex);
}
public void getNextSong() {
// TODO Auto-generated method stub
if(currentIndex == songs.size()-1){
currentIndex=0;
}
else
{
currentIndex=currentIndex+1;
}
playSong(currentIndex);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
mp.start();
return 0;
}
@Override
public void onDestroy()
{
mp.release();
super.onDestroy();
}
}
问题在于它有时打得很好，当我们按下后退按钮或在主屏幕上轻扫其他应用程序时，它会停止。我想在UI上显示标题轨道，图像。但是这段代码显示某些歌曲的错误图像对于某些人来说，即使图像存在，它甚至都不会显示图像。在按下后屏幕之后，当我们使用其他应用程序并回到此时它只显示TextView和正常的android图像。是否需要重新创建活动？我们可以调用吗？服务的活动方法？如何解决问题？请帮帮我。
答案 0 :(得分：0)
您需要背景音乐服务并与活动进行通信以及服务的消息或绑定活动，而不是从服务调用活动方法，这将导致跨进程问题。
我实际上从我写过的商业项目中开源了一个带有后台服务Lyric的音乐播放器，你可以看一下：https://github.com/Wangchao0721/MusicPlayer
但我没有时间填写自述文件，只需查看活动包中的MediaPlayerActivity.java，您就会知道如何使用它。